fs: cifs: cifsssmb: Change return type of convert_ace_to_cifs_ace

Change return from int to void of  convert_ace_to_cifs_ace as it never
fails.

fixes below issue reported by coccicheck
fs/cifs/cifssmb.c:3606:7-9: Unneeded variable: "rc". Return "0" on line
3620

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>